The present invention is in the field of printers and copiers. More specifically this invention relates to a receiver sheet supply and feed apparatus, including a vacuum corrugated feeder, and which may have a positive air pressure separator on such printers and copiers. This invention is useful for the apparatus described by the U.S. Pat. No. 5,344,133 xe2x80x9cVacuum belt feeder having a positive air pressure separator and method of using a vacuum belt feeder xe2x80x9d by Jantsch et al, which patent is hereby incorporated by reference in its entirety. The incorporated patent refers to a vacuum, a first positive air supply, and a second positive air supply. The first and second positive air supplies are used simultaneously and will herein be referred to collectively as the airknife.
In typical reproduction apparatus such as copiers or printers, information is reproduced on individual cut sheets of receiver material such as plain bond paper or transparencies. Such receiver sheets are stored in a stack and fed individually when copies are to be produced. The sheet feeder for the reproduction apparatus must be able to handle a wide range of sheet types and sizes reliably and without damage. Sheets must be fed individually, without misfeeds or multi-feeds.
The vacuum belt feeder described in the incorporated patent is useful for separating the top sheet from a sheet supply stack during the feed cycle. Typically the airflow and vacuum levels and associated timing are dictated by the highest feed rate required from a supply, i.e. one feed every image frame from the same supply. Frequently, this is not the operating mode. For instance, for cover and slipsheet insertion, there are generally a number of xe2x80x98bodyxe2x80x99 sheets fed between insert sheets. Likewise, many printers operate in xe2x80x9cinterleavexe2x80x9d mode when printing duplex whereby every other feed comes from the paper supply interleaved with sheets from the duplex path. In these and similar cases, a method is desired which will separate the top sheet from the sheet supply stack when it is not the feed cycle and thus improve the probability of feeding the next sheet when desired.
A method of operating a vacuum corrugated belt feeder, which may have a positive air pressure separator, during non-feed cycle time so as to separate a sheet from a sheet supply stack, which method comprises agitating the top sheets in the stack by actuating the vacuum and/or the positive air pressure separator during non-feed cycle time.